In the case of channel B, substitutions must be made in Exp. (REF ): \({{\tilde{q}}_{i}}\rightarrow {{\tilde{p}}_{i}},\ {{\tilde{p}}_{f}}\rightarrow {{\tilde{q}}_{f}}\) .
It is important to emphasize that for the given initial parameters (the energy of the initial electron, the intensity and frequency of the wave, the angle between the momenta of the initial electron and the wave) for channel A, the energy of the spontaneous gamma quantum and the final electron is determined only by the outgoing angle of the spontaneous gamma quantum relative to the momentum of the initial electron (parameter \({{\delta ^{\prime }}^2_{\eta i}}\) , see Eq. (REF )).At the same time, for channel B, the energy of the final particles is determined by the angle between the momenta of the spontaneous gamma-quantum and the final electron (the parameter \({{\delta ^{\prime }}^2_{\eta f}}\) , see Exps. (REF ), (REF )-(REF ), (REF ), (REF )). Because of this, channels A and B are distinguishable and do not interfere with each other. In addition, within the same channel (A or B), resonances with a different number of absorbed photons of the wave (a different number \(r\) ) have different frequencies and, therefore, also do not interfere. Taking this into account, it is possible to obtain a resonant differential cross section for each reaction channel separately at fixed values of the number of photons of the wave \(l\)  and \(r\) . At the same time, in the sum by the \(r\)  index in expression (REF ), it is sufficient to leave a specific term with a fixed number of absorbed photons of the wave. Using the expression for the process amplitude (see Exps. (REF )-(REF ), (REF ), (REF )), we obtain an expression for the resonant differential cross section in the case of unpolarized particles. After the standard calculations (see, for example, [1]}) for channel A, we get:
\(d{{\sigma }_{i(l,r)}}=d{{\mathbf {M}}_{i\left(r-l\right)}}\frac{8{{\pi }^{2}{m}^{2}{E}_{f}}}{{\left| \tilde{q}^{2}_{i}-m^{2}_{*} \right|}^{2}}d{\mathbf {K}_{i\left(r\right)}}.\) 
